1. Field
The present disclosure relates generally to telecommunications, and more particularly, to telecommunications involving international dialing
2. Background
Consumer demand for wireless services has led to the development of numerous wireless communication networks. One such network is based on code division multiple access (CDMA) technology which supports wireless voice and data services using spread-spectrum techniques. Spread-spectrum techniques enable high quality service at low cost by efficiently using the available radio frequency (RF) spectrum. As a result, CDMA technology is considered by most to be the next generation of digital wireless communications.
To provide the widest availability of CDMA technology, cost reduction efforts should be employed during implementation. One way to reduce costs is to implement CDMA as an overlay to existing networks such as a Global System for Mobile Communications (GSM). GSM, which has become the de facto standard in Europe and Asia, represents the previous generation of digital wireless communications and utilizes narrowband TDMA to support wireless voice and data services. By implementing CDMA as an overlay to GSM, or other existing systems, reduced cost may be realized because a substantial portion of the existing infrastructure may be used to support CDMA. Within the overlay architecture, the GSM system is augmented to include a CDMA air interface but retain the core GSM network. In operation, a mobile unit will communicate with a base transceiver station (BTS) via the CDMA air interface (instead of the GSM air interface) while the core network remains a conventional GSM network
Implementing a CDMA network as an overlay to an existing infrastructure has various advantages. These include the ability to incrementally introduce CDMA service within a geographic region thereby spreading out the start up cost over time, as well as the ability to perform limited introductions of CDMA service only in areas where demand for wireless services has outgrown the capabilities of existing technology. Additional benefits include providing the performance advantages of the CDMA air interface while avoiding the cost and complexity of replacing the GSM core networks.
Roaming is the ability to make and receive calls outside of a user's home network. International roaming, more specifically, is the ability make and receive calls from a foreign country, using the user's own handset and the foreign country's wireless network. Typically, international roaming requires a user to dial an international access code, or an “international prefix” to reach a telephone number outside of the country where the user is located. International access codes are specific to each country and, in some cases, to the carrier whose network supports the call. For example, a user in the United States must dial “011” on his handset in order to use the international roaming feature to place an international call. A user in France would dial “00,” “40,” or “70,” or another international prefix, depending on which carrier he chooses to utilize, in order to place an international call from France. Therefore, users who frequently travel must keep track of a variety of different international access codes, or prefix, in order to use their handsets to make phone calls in different countries. Because many countries have different international access codes, and because the international access codes within a single country can vary according to carrier, accurate knowledge of the codes can be a significant burden on travelers.
Many European countries utilize the Global System for Mobile Communications (GSM) standard for wireless networks. GSM supports an international dialing feature in which users may dial a (+) key on their handset in lieu of dialing the international prefix. Dialing the (+) key marks the call as an international call, instructing the local switching system to route the call to an international switch. Unfortunately, users whose handsets include the GSM-supported (+) key cannot utilize it in areas that are not covered by a GSM network. For example, code division multiple access (CDMA) air interfaces do not recognize or support such a (+) key functionality and are therefore unable to route a call including that key to an international switch. Instead, in order to route an international call, CDMA systems require the appropriate international prefix to accompany the call.
With the tremendous increase in wireless communications over the past years, there has been a demand for simpler access procedures when roaming internationally. However, there currently does not exist an automated international dialing feature allowing users to engage in international roaming, regardless of the network supporting the call, without knowing and entering the proper international prefix.